Fool's errand - building the fastest numerical computation library

I may or may not end up figuring out how to write my own domain-specific high-performance physics simulators in the near future, but the possibility got me thinking about how to do the underlying calculations in the fastest possible way for any given hardware, from my old ThinkPad to Multi-Processor Multi-GPU racks. Now, I may be a fool but I’m not an idiot, each hardware vendor writes their own set of libraries for these sorts of workloads and I don’t think to outperform them. The idea would b...